ANDROID: arm64: virt: Make the page_relinquish call generic

Move out the kvm specific page_relinquish call and introduce a generic
hypervisor_ops structure. Based on the hypervisor running underneath the
guest, populate the operations to make specific hypercalls.

Bug: 315173520
Change-Id: I93d5a92553a04d56811b0666dec6eacc1ca168e7
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>